Who Leads? Who Follows? Measuring Issue Attention and Agenda Setting by Legislators and the Mass Public Using Social Media Data
By Pablo Barberá, University of Southern California, Andreu Casa, New York University, Jonathan Nagler, New York University, and Patrick J. Egan, New York University, Richard Bonneau, New York University, John T. Jost, New York University, Joshua A. Tucker, New York University
Are legislators more likely to follow the public’s lead in paying attention to different political issues or vice versa? Research demonstrates a strong correspondence between the issues about which the public cares and the issues addressed by politicians, but conclusive evidence about who has the strongest ability to set the political agenda has yet to be uncovered. We shed new light on this question with fine-grained temporal analyses of Twitter messages by legislators and the public during the 113th U.S. Congress. After employing an unsupervised method that classifies tweets sent by legislators and citizens into topics, we use VAR models to explore whose priorities more strongly predict the relationship between citizens and politicians. We find that legislators are more likely to respond to, than to lead, discussion of public issues, results that hold even after controlling for the agenda-setting effects of the media. We also find that legislators are more likely to be responsive to their supporters than to the general public.